Diagnostic devices have traditionally been constructed of non-porous glass or plastic. Analytes such as organic or biochemical molecules have been bound to the devices either by formation of covalent bonds or by hydrophobic interactions.
Such diagnostic devices have been widely used in the biotechnology arena for the qualitative and quantitative analysis of samples. Examples include microtiter/ELISA plates, DNA chips, DNA dipsticks, and bead-based hybridization systems.
Limitations possessed by the currently available devices relate to a) the limited binding capacity of the materials, and b) the accessibility of the bound molecules to other molecules in solution. The flat, two dimensional surface of the materials leads to limited binding capacity. If the binding capacity of the diagnostic device is low, then the sensitivity of assays performed with the device will be low. Similarly, if bound molecules are inaccessible to other molecules in solution, or if the bound molecules adopt unnatural conformations, then the interaction between bound and free molecules will be difficult to assay.
U.S. Pat. No. 5,951,295 (issued Sep. 14, 1999) describes ceramic fused fiber enhanced dental materials, and methods for their preparation. Fused-fibrous material was taught comprising from about 1% to about 50% by weight alumina, from about 50% to about 98% silica, and from about 1% to about 5% by weight boron.
U.S. Pat. No. 5,964,745 (issued Oct. 12, 1999) describes an implantable system for bone or vascular tissue. The system comprises porous linked fibrous biomaterial manufactured from nonwoven, randomly-oriented fibers linked together using a fusion source at a plurality of cross-points into a porous structure, said biomaterial having a plurality of voids of a predetermined mean void size effective for stimulating angiogenesis in said biomaterial from the tissue or bone.
U.S. Pat. No. 5,621,035 (issued Apr. 15, 1997) describes filler compositions and ceramic enhanced dental materials. The preferred embodiment of the filler composition and the ceramic dental restorative material is comprised of about 22% by weight alumina, about 78% by weight silica, about 2% by weight silicon carbide, and about 2.85% by weight boron nitride with less than 1% cristobalite contamination.
Porous materials have been suggested by Yasukawa et al. (U.S. Pat. Nos. 5,629,186 and 5,780,281). A composite was prepared from silica and/or alumina fibers with added boron nitride. The composites were suggested as being useful for cell cultures, implants, and chromatography matrices.
There exists a need for improved diagnostic devices which are capable of binding high concentrations of chemical or biological compounds while maintaining the compounds in an accessible and natural conformation.